Rebecca Thorn
- Sep 3, 2020
- 7 min read

TRAC Beef & Sheep Newsletter - Spring 2020

Results in livestock production systems are ultimately driven by the consistency of feed intake presenting adequate energy for maintenance and performance, protein to support rumen function, and effective fiber to stabilize the process……….simple isn’t it!

We are constantly challenged to meet these requirements which are often impacted by physical, environmental, financial, and emotional influences. 2020 is delivering a new layer of uncertainty but what we can be sure of, our livestock haven’t noticed it. Autumn lambing has been a ripping success in most areas, scanning and lambing % well up on last season, calving results also very good and feed availability generally excellent through this period, setting things up for a positive start to the 2021 breeding season. Ram preparations and positive weight gains for autumn calving cows in current focus.

Winter lambing and spring calving is now in progress with our TRAC Performance Minerals sales team and TRAC Productivity Consultants offering tools and solutions to assist in maintaining consistency through rumen nutrition, delivering practical and topical information.

GETTING THE MOST OUT OF YOUR WINTER PASTURES

With most areas having a drier than average winter, we have seen pastures that have grown at twice the normal growth rate in some areas. For many this has meant that pastures were growing faster than the animals could graze it.

Sounds like a good problem to have right?

Well it does have some negative effects. For the farmers that are set stocked it was probably a good thing as plants were able to increase leaf area allowing, for more available solar panels to harness the energy from the sun. This increased growth then leads to the animals grazing very short leafy material from the grass. When we test the leaf tips we find that the material is high in energy, this is good, super high in protein, however this can cause some problems. Also, super low in fibre, once again more problem here. So our animals are now eating a feed stuff that isn’t balanced and the excess protein and low amount of fibre will have an negative effect on turning grass into meat, milk or wool.

For most of our animal classes on farm, a total diet protein level of 14- 16% CP will be fine. Some of the smaller weaners might need 18% CP but being smaller animals they generally don’t eat too much. Most, if not all, of the pastures and grazing crops that we see on farm at the moment will be substantially higher in Crude protein levels than the animal needs. Well more is better is it not? Well not in the case of protein, first of all we need to understand that all proteins are not created equal. As crude protein percentage is just a calculation (N level x 6.25) we can see forage test that are artificially elevated with nitrogen based fertilisers. Meaning that if I put a big lick of urea on my grass and put the animals on to graze before the urea is all utilised in the plant (normally 21 plus days post spreading), then I risk giving my animals not only nitrate poisoning but I load the animal up with protein that they don’t need. Not only do they not need it, but this potentially toxic amount of protein has to be excreted by the animal. This process involves a lot of energy, pulling unused protein out of the rumen through the rumen wall into the blood filtered by the kidneys, where it is then turned back into urea and excreted via the urine back out onto the pasture. The energy cost on the animal for this process is massive, utilising energy that could have been used to increase fertility, or meat and wool production.

Physically the leaf tips that the animals are eating rapidly turn to soup once it hits the rumen liquor. Having the fed stuff digest so quickly effects the ability for the animal to function as a ruminant but also in many cases the feed stuff flows through the digestive tract so fast that much of it’s energy is digested too late to be absorbed by the animal. Without a level of fibre the animal doesn’t need to chew its cud because there is no rumen raft floating around. The animal chews its cud to break the fibre down even more for digestion, it is also increasing salivation which has levels of bicarb in it to help the animal buffer the rumen from pH drops. The fibre raft also acts like a sieve slowing down the foods passage through the rumen, allowing the bugs more time to break down the feed stuff and extract all available nutrients.

Ok… so how do I help balance out the pasture that I see in the paddocks so that the animals have the best chance to convert that into saleable product? The best way is to block graze the animals using electric fences. By putting grazing pressure on the animal, they are forced to eat the leaf tips and the stems together balancing out the rate of digestion. The animals will convert the feed better as the rapidly digested leaf tips are slowed down by the more fibrous plant stems, allowing for a better-balanced feed. Protein levels in the stem are far lower than the leaf, diluting the final total diet crude protein percentage. If you are unable to restrict your grazing area, then offering the animals a fibre source like straw can be useful. In some cases the animals won’t freely eat the straw, I guess it is like asking your kids to eat veggies when they have ice- cream in front of them!

TPM boost go has been developed to work by slowing down the flow through rate of very digestible grass or cereal crops. The Salt attracts the animals to the free choice minerals and the added bentonite swell in the animal’s rumen physically slowing the rate of passage for the feed stuff. Boost Go’s added Magnesium supplements the usually low levels in plants especially cereals. Low Dietary magnesium levels can lead to grass tetany issues.

Signs that your animals are not utilising the feed stuffs well will be dark loose manure, sometimes with bubbles in it, high dag scores in sheep and animals that are very nervy and easily spooked.

If you need help planning how to best utilise the grass grown this winter, please don’t hesitate to contact the TRAC field staff for a tailor made grazing plan.

MOULD & YEAST IN FORAGES

Our minds are very much still on grass and it feels too early to think about conserved forages, but while we have time it is worth discussing the value of a mould and yeast analyses.

Earlier this year on the 16th of April 2020, Feedworks Australia sent out some information on Moulds and Yeasts in forages, so we have summarised the information and have provided a small checklist to go over when looking to utilise feeds that may be just out of our preferred range.

Check out our article release in August 2020, detailing the guidelines for dealing with mycotoxins produced and managing moulds and yeast in your feeds.

LAMB RUMEN DEVELOPMENT

Let us look at how and why lambs grow, then we can use this information to make informed decisions and understand how to get them out of the door sooner or ready for joining at the correct time through strategic use of grain.

Early on in their life, a lamb’s stomach is more like that of a human type where they absorb the energy from enzymatic digestion of milk intake, also known as a pseudo-monogastric. After not too long, their rumen chambers develop and they are now a true ruminant where they will get 80% of their energy from Volatile Fatty Acids (VFA’s), which are the by-products of what the microbes in the rumen produce. As a result, they are no longer getting the energy from what we feed them, they are getting the energy from the bugs, and we in turn are now feeding the bugs.

There is significant research on the benefits of grain for rumen development, however there is minimal research about the long-term impacts of starting animals on grain early to develop the rumen, to then remove grain and still experience increased digestion without starch sources.

What we do know about early grain feeding:

Imprint feeding is feeding grain to lambs while still on their mothers, this way they are shown how to consume grain in the specific method chosen (e.g. trail feeding) and develop a taste for grain. Therefore when you need to accelerate growth or meet energy needs with grain, they will take to feeding much sooner.

Starchy grains such as wheat and barley develop the rumen in a way that is not possible with grass, hay or milk. The starch in the grain produces propionate and butyrate through microbial fermentation which in turn, grows the papillae which are finger like projections around the inside of the rumen (think of a shaggy towel), the longer and well balanced the grain is the thicker and longer the papillae will become. This increased surface area has more absorption sites for the VFA’s produced by feed. In addition, the butyrate increases vascularisation and growth of blood vessels surrounding the rumen to transport nutrients. A rumen fed grain will appear dark in colour and rough with increased surface area, compared to a rumen without grain that will be light pink and smooth, with much lower surface area.

We know that these developed rumens have significantly better nutrient absorption of VFA’s and better utilisation of feed. However, when the grain is removed the papillae will shrink, therefore the next event you feed grain, a backgrounding period is still essential. What we do not know thoroughly is the time and level of shrinkage on grass, or the impact of vascularisation on continued nutrient transport.

Getting in early means that through periods of high stress such as weaning and when milk declines, grain is an energy dense source of food that takes up little rumen space, allowing them to still eat reasonable amounts of grass or hay. This high energy at a young age, when paired with balanced protein, increases frame size to reach targets earlier and starchy grains power the immune system, weight gain and feed conversion efficiency.

Providing grain at an early age will have direct impacts on rumen development for that time, can increase weight gain and growth and teach them to consume grain when it is critically required. For more information on prepping your lambs, contact your local TRAC Expert...

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